8.1.0: Difference between revisions

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The Secure Monitor was updated.

<check ~~back later for diff>~~

* The SE key read disable function no longer writes zero to AES_KEY_READ_DISABLE/RSA_KEY_READ_DISABLE.

* Functions for locking/checking PMC secure scratch now have additional bitmasks 0x40/0x80 for locking more secure scratch registers.

* NVDEC/TSECB access to the kernel carveout was removed.

* On suspend (SC7 Entry), SWR_USBD_RST is now checked, and AHB arbitration disable is now checked to be COP, ARC, USB, USB2.

** This further mitigates against Deja Vu.

* TZ/SE context save logic has been changed.

** The context save function now first generates 16 random bytes, and securely saves them to scratch (using the usual write-writelock-check-readlock-checklocked pattern).

** It then generates a random aes-256 key, and derives an actual encryption/MAC key by decrypting the random data with that key.

*** Previously, it generated a random aes-256 key and used it directly.

*** This prevents attacks that might coerce the usage of a specific aes-256 key instead of a random one.

** Calls into the check scratch locked/lock scratch function which previously passed one bitmask at a time now pass multiple

*** Accordingly, the lock/check locked functions now support multiple bitmasks instead of single bitmasks at a time.

* The function that initializes the SE/derives keys now sets flag 0x100 on AES keyslots 8-15, and RSA keyslots 0-1.

====Kernel====

@@ Line 22: / Line 22: @@
 The Secure Monitor was updated.
-<check back later for diff>
+* The SE key read disable function no longer writes zero to AES_KEY_READ_DISABLE/RSA_KEY_READ_DISABLE.
+* Functions for locking/checking PMC secure scratch now have additional bitmasks 0x40/0x80 for locking more secure scratch registers.
+* NVDEC/TSECB access to the kernel carveout was removed.
+* On suspend (SC7 Entry), SWR_USBD_RST is now checked, and AHB arbitration disable is now checked to be COP, ARC, USB, USB2.
+** This further mitigates against Deja Vu.
+* TZ/SE context save logic has been changed.
+** The context save function now first generates 16 random bytes, and securely saves them to scratch (using the usual write-writelock-check-readlock-checklocked pattern).
+** It then generates a random aes-256 key, and derives an actual encryption/MAC key by decrypting the random data with that key.
+*** Previously, it generated a random aes-256 key and used it directly.
+*** This prevents attacks that might coerce the usage of a specific aes-256 key instead of a random one.
+** Calls into the check scratch locked/lock scratch function which previously passed one bitmask at a time now pass multiple
+*** Accordingly, the lock/check locked functions now support multiple bitmasks instead of single bitmasks at a time.
+* The function that initializes the SE/derives keys now sets flag 0x100 on AES keyslots 8-15, and RSA keyslots 0-1.
 ====Kernel====